Explore topic-wise InterviewSolutions in Current Affairs.

The gas produced by the anaerobic action of bacteria on biomass is known as biogas. It is preferred over other conventional energy fuels because it is a cleaner fuel, has no foul smell and can be used as a source of energy as it is inflammable.

Flocs are masses of bacteria, associated with fungal hyphae, which form mesh-like structures, during secondary treatment of sewage.

Biogas comprises a mixture of methane, carbon dioxide, hydrogen sulphide and ammonia.

Endosperm forms the kernel of coconut. 

The coconut water is free-nuclear endosperm whereas kernel is cellular endosperm.

Name the asexual reproductive structure produced by penicillium and sponge.

Zoospore  is asexual reproduction structures produced by fungi.

Bud  formation.

A) A government run by the people

D) Freedom to oppose the central values of the Constitution

D) Freedom to oppose the central values of the constitution

The correct answers is Prokaryotes.

Actin and Myosin filaments. 

The instrument which is used to record action potentials generated in the heart muscles is called an electrocardiograph or ECG machine.

Difference between systolic and diastolic pressure is called pulse pressure which is normally 40 mm Hg.

Collagen and elastin fibres.

Angina pectoris is the pain in the chest caused due to reduction in blood supply to cardiac muscle caused due to narrowed and hardened coronary arteries.

The reaction which requires long time for completion i.e. occurs slowly is called slow speed reaction.

Properties of emulsion:

• Emulsion can be diluted with any amount of the dispersion medium. On the other hand, the dispersed liquid when mixed forms a separate layer.
• The droplets in emulsions are often negatively charged and can be precipitated by electrolytes.
• Emulsions show Brownian movement and Tyndall effect.
• The two liquids in emulsions can be separated by heating, freezing, centrifuging, etc.

Oil in water: 

1. Oil is the dispersed phase and water is the dispersion medium. 

2. If water is added, it will be miscible with the emulsion. 

3. Addition of small amount of an electrolyte makes the emulsion conducting. 

4. Continuous phase is water. 

5. Basic metal sulphates, water soluble alkali metal soaps are used as emulsifiers.

Water in oil:

1. Water is the dispersed phase and oil is the dispersion medium. 

2. If oil is added, it will be miscible with the emulsion. 

3. Addition of small amount of an electrolyte has no effect on conducting power. 

4. Continuous phase is oil. 

5. Water insoluble soaps such as those of Zn, Al, Fe, alkaline earth metals are used as emulsifiers.

• Movement of dispersed particles can be prevented by suitable means such as use of membrane. 
• On doing so, it is observed that the dispersion medium begins to move in an electric field. This is known as electroosmosis.

i. A colloidal system in which one liquid is dispersed in another immiscible liquid is called an emulsion.

ii. There are liquid-liquid colloidal systems in which both liquids are either completely or partially immiscible.

iii. There are two types of emulsions :

a. Emulsion of oil in water (o/w type) : 

An emulsion in which dispersed phase is oil and dispersion medium is water is called emulsion of oil in water.

e.g.,

1. Milk consists of particles of fat dispersed in water.

2. Other examples include vanishing cream, paint, etc.

b. Emulsion of water in oil (w/o type) : 

An emulsion in which dispersed phase is water and dispersion medium is oil is called emulsion of water in oil.

e.g.,

1. Cod liver oil consists of particles of water dispersed in oil.

2. Some other examples of this type include butter, cream, etc.

• Adsorption is a surface phenomenon and hence, the extent of adsorption depends upon the surface area of the adsorbent.
• Adsorption increases with an increase in surface area of the adsorbent.
• Finely divided powdered substances provide a larger surface area for a given mass. Hence, a finely divided substance is more effective as an adsorbent.

Chemical adsoiption or chemisorption.

Following are the characteristics of adsorption :

• Adsorption is a surface phenomenon.
• It depends upon the surface area of the adsorbent.
• It involves physical forces (van der Waals forces) or chemical forces (chemical or covalent bonds).
• Adsorbate is always present in higher concentration on the surface of an adsorbent than in the bulk.
• Adsorption is dependent on temperature (of the surface) and pressure (of adsorbate gas).
• It takes place with the evolution of heat (with some exceptions). 

Freundlich proposed the following empirical equation for adsorption of a gas on solid.

\(\frac{x}{m}\) = k P^1/n  (n > 1) ……(i)

Where, 

x = Mass of the gas adsorbed

m = Mass of the adsorbent

\(\frac{x}{m}\) = Mass of gas adsorbed per unit mass of adsorbent

P = Equilibrium pressure k and n are constants which depend on the nature of adsorbate, adsorbent and temperature.

• Adsorption is the phenomenon of accumulation of higher concentration of ‘one substance on the surface of another (in bulk) due to unbalanced/unsatisfied attractive forces on the surface.
• When we write on blackboard using chalk, the chalk particles get adsorbed on the surface of the blackboard.

Hence,

Students can read blackboard written by chalks.

a. Inhibition : 

The phenomenon in which the rate of chemical reaction is reduced by an inhibitor is called inhibition.

b. Electrophoresis : 

The movement of colloidal particles under an applied electric potential is called electrophoresis.

c. Catalysis : 

The phenomenon of increasing the rate of a chemical reaction with the help of a catalyst is known as catalysis.

i. In the given reaction, sodium gets oxidised to sodium oxide (Na2O) and oxygen gets reduced.
ii. In the given reaction, hydrogen getsoxidised to water and copper (II) oxide gets reduced to copper metal.

The chemical substances which bring about reduction by making hydrogen available are called reductant. In the preparation of methane from carbon, hydrogen is a reductant.

Oxidation Reaction: The addition of oxygen (or removal of hydrogen) to a substance is called oxidation. 

(i) C (ii) ZnO

(a) Oxidation; reduction. 

(b) Reduction; oxidation. 

(c) Rancidity.

Sodium is oxidized because it gets oxygen and forms sodium oxide.

(1) Water molecule - b

(2) Haemoglobin molecule - c

(3) Hydrogen atom – a

Silver turns black as it reacts with H₂S present in air and form a layer of Ag₂S.

Copper oxide reduced to copper H₂ changes to water.

Substance oxidised: H₂S 

Substance reduced: SO₂

(1) Neon - (d) 20

(2) Silicon - (c) 28

(3) Chlorine - (a) 35.5

(4) Sulphur - (b) 32

Corrosion of iron is called Rusting.

The component oxidised in the following reaction-

H₂S

(i) This reaction is a type of combination reaction in which reactants combine to form a single product. 

(ii) This reaction is a type of displacement type of reaction in which a reactive reactant displaces the less reactive element from the compound. In the above reaction reactant A displaces B from the compound BC to form a new compound AC. 

(iii) This reaction is a decomposition reaction in which compound A gets dissociated or broken down to form simple products B and C. 

(iv) Double Displacement Reaction is a type of chemical reaction in which anions and cations of the reacting compounds exchange their positions to form different compounds. This reaction is a double displacement type of reaction.

Corrosion is a process in which metals, are deteriorated by action of air, moisture, chemicals etc.

In a chemical change, two substances react chemically to form new substances with different properties.

C) Photo chemical

Electrolytic reduction

Chemical reactions are characterized by one or more of the following characteristics – the evolution of gas, change of color, formation of a precipitate, energy changes, and change of state.

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy 

It is an exothermic reaction because of a large amount of heat is released.

Example: Decomposition of vegetable matter into compost.

In a chemical reaction, the number of atoms of the elements in the reactants is same as the number or atoms of those elements in the product, such an equation is called a balanced equation.

Example: AgNO₃ + NaCl → AgCl + NaNO₃

In the above reaction, the number of atoms of the elements in the reactants is same as the number of atoms of elements in the products.

Hydrogen peroxide decomposes into H₂O and O₂ in the presence of sunlight and hence to prevent decomposition, they are kept in coloured bottles.

2H₂O+Sunlight→2H₂O+O₂

(a) Combination. 

(b) Decomposition. 

(c) Decomposition. 

(d) Decomposition. 

(e) Combination.

1. Decomposition. 

2. Combination. 

3. Decomposition. 

4. Decomposition. 

5. Combination.